Construction and mining equipment include various mechanical elements and systems that must be powered during operation. Paving machines, for example, are typically used for building roadways, parking lots, and the like, and function to deposit paving material, such as asphalt, on a paving surface to create a flat, consistent surface over which vehicles may travel. A paving machine at a construction site, such as an asphalt paver, is generally a state-of-the art self-propelled construction machine designed to receive, convey, distribute, profile and partially compact the asphalt material. The paving machine or tractor accepts heated asphalt material into a receiving hopper at the front of the machine, which is conveyed to the rear of the machine with parallel slat conveyors or other types of conveyors positioned at the bottom of the hopper. The asphalt material conveyed from the hopper is distributed along the width of an intended ribbon or mat by means of two spreading conveyors or opposing augers. The paving machine may further employ a screed towed behind the tractor and having vibratory and/or tamper mechanisms and heating elements to profile and compact the asphalt material into a mat on the paving surface.
The operation of the paving machine and its components may be manually controlled by an operator to dispense the asphalt material and create the mat on the paving surface. In many paving machines, systems are provided to automate and control the paving process for consistent operation of the paving machine for laying a uniform mat on the paving surface without defects compromising the integrity and longevity of the mat. The automation systems may include control over the speed of the paving machine, operation of the conveyors and augers to distribute the asphalt material, vertical positioning and temperature control of the screed, control of the screed or tamper vibrations, regulation of air ventilation and circulation through the machine and over the other mechanical and electrical elements, and the like. The control settings may be established during an initial setup process for a paving job, such as the paving of a stretch of a highway or the paving of a parking lot. Other construction and mining equipment typically have similar automation systems for performing the operations for which they are designed.
During the paving process, the various systems of the paving machine, such as the conveyors and the augers, propulsion and steering mechanisms, ventilation and cooling systems, hopper, auger and screed positioning systems, and screed tampers and heaters, operate as discussed above to form the desired mat in the manner known to those skilled in the art. Many or all of these systems may be driven by hydraulic pumps or motors which are indirectly operated by the power source of the paving machine. In typical paving machines, for instance, a power source, such as a gas or diesel internal combustion engine, has an output shaft which drives a pump drive. The pump drive, in turn, drives multiple pumps and/or motors providing pneumatic, hydraulic and mechanical power to the various systems of the paving machine.
This string of interconnected components as described results in parasitic losses and reduced efficiency that increase the overall cost of operating the machine. Actual implementation of such systems also tends to occupy more space on the paving machine, tractor and screed assembly and require fluid lines to be run between the pumps and motors and the driven elements. Some paving machine arrangements provide a more direct connection between a power source and a generator to provide power to electrical elements. For example, U.S. Pat. No. 8,636,442, issued on Jan. 28, 2014 and entitled, “Integrated Generator for Screed Plate Heat Up,” discloses a paving machine with a power source such as an internal combustion engine that drives a pump drive with an integrated generator. The integrated generator outputs AC power to a power converter that in turn outputs DC power to a power distribution box in the screed for distribution of the power to the screed heating elements. The integrated generator provides power to the screed heating elements, but the paving machine still utilizes the pump drive and other hydraulic pumps and motors to provide power to the other mechanical elements. Moreover, a starter motor for turning over the engine and an alternator for charging the battery and powering the electrical systems when its engine is running are still implemented in paving machines.
In view of the inefficiencies and performance risks present in providing power to the mechanical elements and systems in the present paving machines and other construction and mining equipment, a need exists for improved electrical power generation and transmission within the machines during operation.